Why does a DMM behave strangely measuring AC currents

Question

I am using a digital DMM (Digitech QM1535) to measure the current drawn by currents at my switchboard. We have a higher thn expected power bill, so I pulled fuses and measured currents in the various circuits to see if one was unexpectedly high.

On a lighting circuit with about 1Kw of incandescent bulbs attached I get a reading of 21A. Yeah right. Further, an ammeter should pass th current through, bringing the lights on. Not so.

The meter works fine on all other ranges and neither internal fuse is blown.

I feel I am doing something fundamentally wrong. I am quite conversant with home and commercial wiring though never done this test before. I am inclined to blame the meter. Can anyone shed light on why this is happening?

Selecting different ranges manually (its a fully auto meter) I get different but very high currents. And why aren't the circuits becoming active with th meter in series? An ammeter has a very low forward resistance.

Any help would be appreciated.

And please, no lectures on mains voltage dangers - I have a background in electronics and building wiring spanning 25 years so I'm not wantin a diatribe on how ikely I am to kill myself.

Thanks everyone.

Answer 1

very weird. i will need to follow this question. i cant think of anything it could be besides the meter. the biggest thing is how the lights dont come on when measuring. amp clamps are always the best ($!).